Worried to start anti-thyroid drug and weight gain

[Luna2017]

Hi, I am new to this site and was diagnosed with an overactive thyroid a few days ago. Other than a racing heart I have been very lucky and haven’t actually felt too bad (TSH 0.02 and T4 46.3) my doctor has started me on 10mg carbimazole daily and I am really anxious about the weight gain since I haven’t actually lost weight even with the overactive thyroid. Has anyone got any advice? I am just being paranoid? Thank you in advance!

[gimel]

You should be tested on a regular basis for the biologically active thyroid hormones, Free T4 and Free T3 (not Total T4 and Total T3) to make sure that your anti-thyroid med is adequately adjusted, in order to prevent switching over and becoming hypothyroidism.  I would say that you want both your Free T4 and Free T3 in the upper half of their ranges.   In addition, since hypothyroidism is correctly defined as "insufficient T3 effect in tissue throughout the body due to inadequate supply of, or response to, thyroid hormone",  it would also be a good idea to test for cortisol,  Vitamin D, B12 and ferritin.  All affect the response to thyroid.  Cortisol should be neither too high or too low.  For the other 3 you can supplement as needed to optimize.
D should be at least 50 ng/mL, B12 in the upper end of its range and ferritin should be at least 100.

If you follow this and get the needed tests and make adjustments to your meds /supplements as suggested you should not have to worry about hypothyroid symptoms like ASA96 mentioned.   Most important will be your dose of  Carbimazole.  

[ASA96]

Hi Luna,  I am definitely not an expert however I will advice you to do a lot of research and get a second opinion.  Years ago I was diagnosed with an overactive thyroid just like you, I felt fine and was always very thin.  The only problem I had was constant headaches and that was the reason why my Doctor checked my thyroid.  He recommended radiation to get rid of my thyroid due to the lack of medicine for hyper thyroid.  Looking back now I wish I had asked more questions or gotten a second opinion.  After removing my thyroid I have had nothing but problems, with hair loss, weight gain, sensitivity to cold, dry skin and anxiety.  Hope this helps!